From: Dave Hansen <dave.hansen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
To: Vlastimil Babka <vbabka-AlSwsSmVLrQ@public.gmane.org>,
Florian Weimer <fweimer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
linux-x86_64-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: linux-mm <linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org>,
Linux API <linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: MPK: removing a pkey
Date: Thu, 23 Nov 2017 07:00:32 -0800 [thread overview]
Message-ID: <17831167-7142-d42a-c7a0-59bdc8bbb786@linux.intel.com> (raw)
In-Reply-To: <de93997a-7802-96cf-62e2-e59416e745ca-AlSwsSmVLrQ@public.gmane.org>
On 11/23/2017 12:11 AM, Vlastimil Babka wrote:
>> No, the default is clearly 0 and documented to be so. The PROT_EXEC
>> emulation one should be inaccessible in all the APIs so does not even
>> show up as *being* a key in the API. The fact that it's implemented
>> with pkeys should be pretty immaterial other than the fact that you
>> can't touch the high bits in PKRU.
> So, just to be sure, if we call pkey_mprotect() with 0, will it blindly
> set 0, or the result of arch_override_mprotect_pkey() (thus equivalent
> to call with -1) ? I assume the latter?
It's supposed to set 0.
-1 was, as far as I remember, an internal-to-the-kernel-only thing to
tell us that a key came from *mprotect()* instead of pkey_mprotect().
WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave.hansen@linux.intel.com>
To: Vlastimil Babka <vbabka@suse.cz>,
Florian Weimer <fweimer@redhat.com>,
linux-x86_64@vger.kernel.org, linux-arch@vger.kernel.org
Cc: linux-mm <linux-mm@kvack.org>, Linux API <linux-api@vger.kernel.org>
Subject: Re: MPK: removing a pkey
Date: Thu, 23 Nov 2017 07:00:32 -0800 [thread overview]
Message-ID: <17831167-7142-d42a-c7a0-59bdc8bbb786@linux.intel.com> (raw)
Message-ID: <20171123150032.6F9mRf7_q1WiiAZ9RXfar-smfRX12vn3mXXCRoueN-w@z> (raw)
In-Reply-To: <de93997a-7802-96cf-62e2-e59416e745ca@suse.cz>
On 11/23/2017 12:11 AM, Vlastimil Babka wrote:
>> No, the default is clearly 0 and documented to be so. The PROT_EXEC
>> emulation one should be inaccessible in all the APIs so does not even
>> show up as *being* a key in the API. The fact that it's implemented
>> with pkeys should be pretty immaterial other than the fact that you
>> can't touch the high bits in PKRU.
> So, just to be sure, if we call pkey_mprotect() with 0, will it blindly
> set 0, or the result of arch_override_mprotect_pkey() (thus equivalent
> to call with -1) ? I assume the latter?
It's supposed to set 0.
-1 was, as far as I remember, an internal-to-the-kernel-only thing to
tell us that a key came from *mprotect()* instead of pkey_mprotect().
WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave.hansen@linux.intel.com>
To: Vlastimil Babka <vbabka@suse.cz>,
Florian Weimer <fweimer@redhat.com>,
linux-x86_64@vger.kernel.org, linux-arch@vger.kernel.org
Cc: linux-mm <linux-mm@kvack.org>, Linux API <linux-api@vger.kernel.org>
Subject: Re: MPK: removing a pkey
Date: Thu, 23 Nov 2017 07:00:32 -0800 [thread overview]
Message-ID: <17831167-7142-d42a-c7a0-59bdc8bbb786@linux.intel.com> (raw)
In-Reply-To: <de93997a-7802-96cf-62e2-e59416e745ca@suse.cz>
On 11/23/2017 12:11 AM, Vlastimil Babka wrote:
>> No, the default is clearly 0 and documented to be so. The PROT_EXEC
>> emulation one should be inaccessible in all the APIs so does not even
>> show up as *being* a key in the API. The fact that it's implemented
>> with pkeys should be pretty immaterial other than the fact that you
>> can't touch the high bits in PKRU.
> So, just to be sure, if we call pkey_mprotect() with 0, will it blindly
> set 0, or the result of arch_override_mprotect_pkey() (thus equivalent
> to call with -1) ? I assume the latter?
It's supposed to set 0.
-1 was, as far as I remember, an internal-to-the-kernel-only thing to
tell us that a key came from *mprotect()* instead of pkey_mprotect().
--
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next prev parent reply other threads:[~2017-11-23 15:00 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-05 10:35 MPK: pkey_free and key reuse Florian Weimer
2017-11-05 10:35 ` Florian Weimer
2017-11-05 10:35 ` Florian Weimer
2017-11-08 20:41 ` Dave Hansen
2017-11-08 20:41 ` Dave Hansen
2017-11-09 14:48 ` Florian Weimer
2017-11-09 14:48 ` Florian Weimer
2017-11-09 14:48 ` Florian Weimer
2017-11-09 16:59 ` Dave Hansen
2017-11-09 16:59 ` Dave Hansen
2017-11-09 16:59 ` Dave Hansen
2017-11-23 12:48 ` Florian Weimer
2017-11-23 12:48 ` Florian Weimer
2017-11-23 13:07 ` Vlastimil Babka
2017-11-23 13:07 ` Vlastimil Babka
2017-11-23 15:25 ` Dave Hansen
2017-11-23 15:25 ` Dave Hansen
2017-11-24 14:55 ` Florian Weimer
2017-11-24 14:55 ` Florian Weimer
[not found] ` <0f006ef4-a7b5-c0cf-5f58-d0fd1f911a54-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-11-22 8:18 ` MPK: removing a pkey (was: pkey_free and key reuse) Vlastimil Babka
2017-11-22 8:18 ` Vlastimil Babka
2017-11-22 8:18 ` Vlastimil Babka
2017-11-22 12:15 ` MPK: removing a pkey Florian Weimer
2017-11-22 12:15 ` Florian Weimer
2017-11-22 12:15 ` Florian Weimer
2017-11-22 12:46 ` Vlastimil Babka
2017-11-22 12:46 ` Vlastimil Babka
2017-11-22 12:46 ` Vlastimil Babka
[not found] ` <f0495f01-9821-ec36-56b4-333f109eb761-AlSwsSmVLrQ@public.gmane.org>
2017-11-22 12:49 ` Florian Weimer
2017-11-22 12:49 ` Florian Weimer
2017-11-22 12:49 ` Florian Weimer
2017-11-22 16:10 ` Dave Hansen
2017-11-22 16:10 ` Dave Hansen
2017-11-22 16:21 ` Florian Weimer
2017-11-22 16:21 ` Florian Weimer
2017-11-22 16:21 ` Florian Weimer
[not found] ` <9ec19ff3-86f6-7cfe-1a07-1ab1c5d9882c-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-11-22 16:32 ` Dave Hansen
2017-11-22 16:32 ` Dave Hansen
2017-11-22 16:32 ` Dave Hansen
2017-11-23 8:11 ` Vlastimil Babka
2017-11-23 8:11 ` Vlastimil Babka
[not found] ` <de93997a-7802-96cf-62e2-e59416e745ca-AlSwsSmVLrQ@public.gmane.org>
2017-11-23 15:00 ` Dave Hansen [this message]
2017-11-23 15:00 ` Dave Hansen
2017-11-23 15:00 ` Dave Hansen
2017-11-23 21:42 ` Vlastimil Babka
2017-11-23 21:42 ` Vlastimil Babka
[not found] ` <2d12777f-615a-8101-2156-cf861ec13aa7-AlSwsSmVLrQ@public.gmane.org>
2017-11-23 23:29 ` Dave Hansen
2017-11-23 23:29 ` Dave Hansen
2017-11-23 23:29 ` Dave Hansen
2017-11-24 8:35 ` Florian Weimer
2017-11-24 8:35 ` Florian Weimer
2017-11-24 8:38 ` Vlastimil Babka
2017-11-24 8:38 ` Vlastimil Babka
2017-11-23 12:38 ` Florian Weimer
2017-11-23 12:38 ` Florian Weimer
2017-11-23 15:09 ` Dave Hansen
2017-11-23 15:09 ` Dave Hansen
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